Download Muscles of the Head - Coach Frei Science

THE NAMING OF MUSCLES
And Muscles of the Head and Neck
Naming Muscles
 Muscles are named according to:
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Location (frontalis – forehead)
Size (gluteus maximus)
Direction (external abdominal oblique)
Number of origins (biceps femoris)
Location of origin and insertion
(sternocleidomastoid)
 Action (flexor carpi ulnaris)
 Shape (deltoid – triangular)
MUSCLES OF THE HEAD
 There are 656 muscles in the human body.
 327 of these muscles are in antagonistic pairs (654)
 2 muscles are unpaired
 orbicularis oris
 diaphragm
Head Muscles
 Have many specific functions.
 Are grouped into 2 categories:
1. Facial muscles
 Provide movement for facial expressions
 Are unique in that they insert into soft tissues such
as other muscles or skin
2. Chewing muscles
 Control the mandible for mastication
 Begin the breakdown of food in the digestive
process
Facial Muscles
Frontalis
 Covers the frontal bone
 Starts at the cranial aponeurosis (a thin sheath of
connective tissue that cover the crown of the skull)
and inserts at the skin of the eyebrows.
 Functions to raise eyebrows
and wrinkle the forehead
Occipitalis
 Covers the posterior portion of the cranium.
 Starts at the back part of the cranial aponeurosis and
connect to the skin at the back of the head.
 Functions to pull the scalp posteriorly (used for
wiggling your ears)
Orbicularis Oculi
 Has fibers that run in a circular pattern around the
eye. Also lies underneath the eyebrows.
 Functions to close your eyes, squint, blink, and wink.
Also tightens the skin on the forehead.
Orbicularis Oris
 A circular muscle that surround the opening of the
mouth.
 Functions to close and compress the lips. Also allows
you to protrude your lips.
 AKA the “kissing” muscle
Muscles that move the
orbicularis oris
A. Levator labii superioris nasi
B. Levator labii superioris
C. Zygomaticus minor
D. Zygomaticus major
E. Levator anguli superioris
F. Orbibularis oris
G. Node (corner of mouth)
H. Risorius
I. Platysma
J. Despressor anguli oris
K. Depressor labii inferioris
L. Mentalis
Buccinator
 A horizontal muscle that runs across the cheek
starts at the lateral angle of the mandible and
inserts into the orbicularis oris.
 Functions to flatten the cheek (when whistling or
blowing a trumpet).
 Also somewhat involved in chewing. It
compresses the cheek to hold food in between the
teeth during chewing.
Zygomaticus
 Extends from the corner of the mouth to the
cheekbone at a diagonal.
 This muscle has two bodies:
 major the larger of the two, found more laterally
 minor the smaller of the two, found more medially
 Functions to raise the corners of the mouth.
 Is often referred to as the “smiling” muscle.
zygomaticus
Depressor Anguli Oris
 Originates along the side of the chin and tapers to
inserts at the corner (node) of the orbicularis oris.
 Functions to depress or pull down the corners of
the mouth.
Nasalis
 Two sets of muscles
located over the nasal
bones.
 One is lateral
 One is vertical
 Functions to close and
open the nasal opening.
 Allows you to flare and
close your nostrils.
Muscles of Mastication
Masseter
 Runs from the zygomatic process of the
temporal bone to the mandible.
 Covers the lateral surface of the angle of the
lower jaw.
 Is the primary muscle involved in closing the
jaw; does so by elevating the mandible.
Temporalis
 A fan-shaped muscle overlying the temporal
bone.
 Passes underneath the zygomatic process and
inserts into the mandible.
 Acts as a synergist of the masseter.
 Functions to raise the jaw and draw the jaw
backward.
Neck Muscles
 For the most part, these muscles move the
head and the shoulder girdle.
 These muscles cause the head:
 Extension
 Flexion
 Rotation
Platysma
 A broad, sheet-like muscle that covers the
anterolateral surface of the neck.
 Orginates from the connective tissue covering the
chest muscles and inserts into the area around the
mouth.
 Functions to pull the lower jaw inferiorly and
backward.
 Sternocleidomastoid
 Paired muscles found diagonally on each side of the
neck.
 Originates at two places:
 from the sternum
 from the clavicle
 The heads fuse and insert into the mastoid process of
the temporal bone.
 If both contract, functions to flex the neck.
 If one contracts, the head is rotated.
Identify the muscles that are
being used in the following
facial expressions.